IDEAL GAS LAW
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An ideal gas is defined as one in which all collisions between atoms or molecules are perfectly eleastic and in which there are no intermolecular attractive forces. One can visualize it as a collection of perfectly hard spheres which collide but which otherwise do not interact with each other. In such a gas, all the internal energy is in the form of kinetic energy and any change in internal energy is accompanied by a change in temperature.
An ideal gas can be characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them may be deduced from kinetic theory and is called the IDEAL GAS LAW: PV=nRT n = number of moles R = universal gas constant = 8.3145 J/mol K N = number of molecules k = Boltzmann constant = 1.38066 x 10-23 J/K = 8.617385 x 10-5 eV/K k = R/NA NA = Avogadro's number = 6.0221 x 1023 /mol The ideal gas law can be viewed as arising from the kinetic pressure of gas molecules colliding with the walls of a container in accordance with Newton's laws. But there is also a statistical element in the determination of the average kinetic energy of those molecules. The temperature is taken to be proportional to this average kinetic energy; this invokes the idea of kinetic temperature. One mole of an ideal gas at STP occupies 22.4 liters. |
Check out this video and solve the problems below.1. A hydrogen gas thermometer is found to have a volume of 100.0 cm3 when placed in an ice-water bath at 0°C. When the same thermometer is immersed in boiling liquid chlorine, the volume of hydrogen at the same pressure is found to be 87.2 cm3. What is the temperature of the boiling point of chlorine?
2. When filling a weather balloon with gas you have to consider that the gas will expand greatly as it rises and the pressure decreases. Let’s say you put about 10.0 moles of He gas into a balloon that can inflate to hold 5000.0L. Currently, the balloon is not full because of the high pressure on the ground. What is the pressure when the balloon rises to a point where the temperature is -10.0°C and the balloon has completely filled with the gas. 3. At what temperature would 2.10 moles of N2 gas have a pressure of 1.25 atm and in a 25.0 L tank? |